2026, November 17: Voyager 1 Reaches One Light Day from Earth

November 17, 2026: Voyager 1 reaches one light-day from Earth tomorrow morning. Explore the spacecraft’s Grand Tour, gravity assists, historic planetary encounters, and continuing signals from interstellar space.

This is an image of the planet Uranus taken by the spacecraft Voyager 2 in 1986. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.
Photo Caption – This is an image of the planet Uranus taken by the spacecraft Voyager 2 in 1986. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

by Jeffrey L. Hunt

Chicago, Illinois: Sunrise, 6:43 a.m. CDT; Sunset, 4:28 p.m. CST.  Times are calculated by the US Naval Observatory’s MICA computer program. Check local sources for sunrise and sunset times.

One Light Day

Tomorrow at 4:16 a.m. Central Time, the Voyager 1 spacecraft is expected to be one light-day from Earth. A light-day is the distance light travels in 24 hours. Two-way communication with the spacecraft takes two days for a round trip response.

With your calculator, find this product: 186,000 miles/second × 60 seconds/minute × 60 minutes/hour × 24 hours/day. The result is 16,070,400,000 miles, or about 16.1 billion miles.

Grand Tour

Voyager paths
Chart Caption – Voyager 1 and 2 paths from Earth past the outer planets (NASA)

In the 1960s, NASA scientists recognized that the outer planets would be favorably aligned in the late 1970s and 1980s. They realized they could use a large planet’s gravity to change a spacecraft’s direction and increase its speed. This maneuver is known as a gravity assist. It reduces the amount of propellant needed and can shorten a spacecraft’s journey.

A Grand Tour of the large planets was planned, although the original program was canceled because of its projected cost. NASA approved a scaled-down mission in 1972, eventually named Voyager, with two spacecraft. Voyager 2 was launched on August 20, 1977, followed 16 days later by Voyager 1.

Jupiter Movie
Image Caption – This movie records the approach of Voyager 1 during a period of over 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. (NASA/Caltech)

Voyager 1 passed Jupiter in March 1979 and Saturn in November 1980. Voyager 2 passed Jupiter in July 1979 and Saturn in August 1981. Voyager 2 continued to Uranus in January 1986 and Neptune in August 1989.

The spacecraft sent back photographs and scientific data that transformed our knowledge of the giant planets and their moons.

Saturn
Image Caption: NASA Voyager 2 took this true color photograph of Saturn on July 21, 1981. The moons Rhea and Dione appear as blue dots to the south and southeast of Saturn, respectively. (NASA/Caltech)

Voyager

Both spacecraft have experienced equipment failures and dwindling electrical power from their radioisotope thermoelectric generators. These generators use heat from radioactive decay to produce electricity, losing about four watts of output each year. Some instruments have been turned off to conserve power.

Voyager Spacecraft
Chart Caption – Schematic of Voyager spacecraft (NASA)

Their feeble radio signals from approximately 20-watt transmitters and 12-foot high-gain antennas are captured by the large radio receivers of the Deep Space Network.

This contrast enhanced color picture of Neptune was acquired by Voyager 2 at a range of 14.8 million kilometers (9.2 million miles) on August 14, 1989. (NASA photo)
Photo Caption – This contrast enhanced color picture of Neptune was acquired by Voyager 2 at a range of 14.8 million kilometers (9.2 million miles) on August 14, 1989. (NASA photo)

Voyager 1’s trajectory was modified to pass closely to Saturn’s large moon Titan. That encounter bent the spacecraft’s path northward, away from the ecliptic. Voyager 1 is now about 35° north of the ecliptic and, at sunset, its direction is about 40° above the western horizon, if it were visible to the unaided eye.

Similarly, Voyager 2 is not visible and is always below the horizon from mid-northern latitudes. Traveling slower, Voyager 2 is expected to reach one light-day from Earth in November 2035.

Today’s Notes

  • Venus, Mercury, Spica, November 17, 2026
    Chart Caption -2026, November 17: Venus and Mercury are in the east-southeast before sunrise.
  • Jupiter, Mars, Regulus, November 17, 2026
    Chart Caption – 2926, November 17: An hour before sunrise, Jupiter and Mars are high in the southern sky near Regulus.
  • Moon, November 17, 2026
    Chart Caption – 2026, November 17: An hour after sunset, the moon is in the southern sky.
  • Saturn, November 16, 2026
    Chart Caption – 2026, November 17: Saturn is in the east-southeast after sunset.

Today’s charts – click the arrows to shuttle through them

  • An hour before sunrise, look for brilliant Venus nearly 20° above the east-southeast horizon and 1.6° to Spica’s upper left. Mercury is over 6° above the horizon and 13° to Venus’ lower left.
  • Higher in the south, bright Jupiter is in front of Leo, 4.2° to Regulus’ upper right. Mars is 1.3° to Jupiter’s upper left. Watch Mars overtake Regulus. Mars passes the star on November 26.
  • After sunset, the moon, 54% illuminated, is 35° above the southern horizon.
  • Farther eastward, Saturn is over 30° above the east-southeast horizon and 35° to the moon’s left.

Tomorrow, Voyager 1 reaches a milestone distance. Two of its instruments continue to collect data from the depths of space and send it home through its feeble transmitter. In the sky, look for Venus, Jupiter, Mercury, and Mars before sunrise, while the moon and Saturn can be seen after sunset.

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